Scaffold



(No Model.)

B. J. O RUMP. SOAPPOLD.

No. 423,989. Patented Mar. 25, 1890.

iiiiorne UNITED STATES lATENT OFFIcn.

ROBERT J. CRUMP, OF OWENSBOROUGH, KENTUCKY.

SCAFFOLD.

SPECIFICATION forming part of Letters Patent No. 423,989, dated March25, 1890.

Application filed December 16, 1889. fierial No. 333,918. (No model.)

To all whom it may concern:

Be it known that I, ROBERT J. CRUMP, a citizen of the United States,residing at Owensborough, in the county of Daviess and State ofKentucky, have invented certain new and useful Improvements inScafiolds; and I do declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, and to the letters of reference markedthereon, which form a part of this specification.

This invention has relation to certain new and useful improvements inscaffolds for the use of painters, brick-layers, and others; and it hasfor its object among others to provide an improved device of thischaracter which shall be simple, easily operated, and durable.

The novelty in the present instance resides in the peculiarities ofconstruction and the combinations, arrangement, and adaptation of parts,all as more fully hereinafter described, shown in the drawings, and thenparticularly pointed out in the appended claim.

The invention is clearly illustrated in the accompanying drawings,which, with the letters of reference marked thereon, form a part of thisspecification, and in which Figure 1 is aperspective View of a scaffoldconstructed in accordance with my invention.

Fig. 2 is a detail which will be more particularly hereinafter referredto.

Like letters of reference indicate like parts throughout the severalviews.

Referring now to the details of the drawings by letter, A designatessuitable uprights suitably braced or supported at their lower ends, andalso by means of the longitudinal pieces A, which are adjustably held tothe uprights by means of the thumb-bolts a, passing through theelongated slots in the ends of the said longitudinal pieces. The upperends of each set of uprights is preferably braced by a cross piece orcap A Near the upper ends of these uprights beneath these caps arejournaled the rollers or drums B, provided near each end with acircumferen tial groove 1), in which the hoisting ropes or chains aredesigned to work. These rollers or drums taper slightly from the innerwall of the grooves toward the center of the roller or drum, as shownclearly in Fig. 1, for a purpose hereinafter made apparent. Near thelower ends of the uprights are journaled the larger drums 0, each havingan extended end provided with a crank and handle 0, by means of whichthe said drums maybe caused to revolve when it is desired to elevate theplatform.

The platform D consists of the transverse timbers D, having their endscut away to embrace the uprights, and are thus guided in their verticalmovement, and the longitudinal timbers D connecting said transversetimbers and attached thereto in any suitable manner. This platform isdesigned to receive the material and the laborers, and is elevated inthe following manner: E are ropes or chains, two at each end of thescaffold, one end of each rope or chain being attached to the lowerdrums, and after passing over the upper drums are secured to thetransverse end tim bers of the platform. The turning of the cranks onthe extended ends of the journals of the lower drums causes the platformto rise. In order to prevent retrograde movement of the platform, Iprovide upon one end of each of the lower drums a ratchet-wheel F, withwhich is designed to engagea gravity pawl or dog G, pivoted to the innerface of the uprights at that side of the scaffold. As the platform risesthe dogs automatically engage the teeth of the ratchet-wheel and preventretrograde movement of the platform and drums. These dogs are upon theinner faces of the uprights, where they are not liable to injury. Thetaper of the upper drums or rollers from each end toward the center isdeemed of special importance, as it serves to draw the ropes or chainstoward the ends of the rollers into the grooves therefor, and thusprevent overrunning or interfering of the two ropes or chains whichtravel or work on each upper drum or roller. If the cords or chainsshould get out of their grooves in the lowering of the platform, as isliable sometimes to occur, they will be automatically drawn outward awayfrom each other as the platform is elevated.

What is claimed as new is- The combination, with the uprights and theeach end of the platform, substantially as IO vertica1ly-1n0vableplatform, of the lower shown and described, and for the purpose drumsjonrnaled in said uprights and prospecified. vicled with cranks upontheir extended ends, In testimony whereof I aifix my signaturein 5 thecords or chains attached at one end to presence of two witnesses.

said platform and at the other to the lower ROBERT J. CRUMP. drums, andthe upper drums j onrnaled in said Witnesses: uprights and tapered fromtheir ends toward J. D. ATCHISON,

the center, and over which pass two cords at THOS. R. HIGGINS.

